Device for counting bacteria and the like



May 9, 1939. s P. SPARKS DEVICE FOR COUNTING BACTERIA AND THE LIKE 2 Sheets-Sheet l Filed May l0, 1957 4 ZI-A |-i .LILv m55 INVE SHERMAN P. SPA NTOR.

ATT NEY May 9, 1939. s. P. SPARKS 2,157,438

DEVICE FOR COUNTING BACTERIA AND THE LIKE Filed May 10, 1957 2 Sheets-Sheet 2 I,0OO|000 |.0

0 2 4 B 6 Y e lo l2 Fig. 5 SHERMAN p. SPARKS INVENTOR.

Patented May 9, 1939 f PATENT OFFICE zfismss nrviol: ron ooUNTlNG momma AND 'ras Sherman P. Sparks, Mount Olive, Ill.

Application May 10, 1937, Serial No. 141,731

2 Claims.

This invention relates to devices fordetermining the number ofbacteria present in liquid bacterial culture at varying intervals during the process of incubation and multiplication, and particularly to that type of device for counting the number of organisms present, based on the,

turbidity of the liquid media and culture.

An object of my invention is to provide means for determining the relationship between the number of organisms in a liquid media and its turbidity.

Another object of my invention is to provide in a device of this type relatively rapid means for revealing in terms of foot-candles the number of organisms in liquid media and culture.

A further object of my invention is to provide in connection with a device of this type means for visual and graphic interpretation of the footcandle readings in a manner to affect as well the ready charting of conditions evident at reading intervals, the total time consumed for a complete` count, and the multiplication of organisms in the liquid media over a set time period.

A still further object of my invention is the provision therein of Van adjustable light source toi facilitate the ready standardization of media for use in various types of work and experiments.

A further purpose is to provide simple andt novel means for holding various sizes of test tubes in position to permit the direction of light rays therethru.

vAnother purpose is to provide simple and novel structure for supporting a potoelectric cell which in co-operation with a foot-candle meter is ink turn adapted to indicate in terms of foot-candles the turbidity of iluid'wlthin the test tube.

It is my purpose to provide such an apparatus that may be used with different foot-candle meter scale panels which may be changed for the purpose of' running tests with different types 'of media.

It is also a-purpose of my invention to provide novel features hereinafter more fully set forth in the structure of the closure for the device.

With these and other objects in view, my invention consists in the construction, arrangement, and combination of the various parts of my turbidimeter, whereby the objects contemplated are attained, as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawings, in which:

Fig. 1 is a .side sectional View of my improved turbidimeter, parts being shown in elevation.

Fig. 2 is a top plan view of my improved turbidimeter, part of the lid of the closure being 'broken away.

Fig. 3 is a fragmentary perspective from the front end of my turbidimeter.

Fig. 4 is a plan view of the scale panel of the foot-candle meter in my turbidimeter, the double view taken graph made from an actual turbidity test made with my improved turbidimeter.

My device includes certain facilities and means as will be readily apparent to those skilled in the art, by reference to the specication, claims and drawings referring to my improved turbidimeter, for rendering it adaptable for handling liquid bacterial culture and the like, or,l for handling ingredients which may beheld in temporary or permanent suspension in liquid, such as gun powder, face powder, paint pigments and the like, to determine the size of and iix the standards of said powder and pigments, for, while the larger granules or particles settle out of suspension, leaving the smaller ones suspended to settle slower, the size of the grind or individual powder particles may be noted and governed for the purpose of standardization or for varying the quality of the products mentioned.

In the accompanying drawings I have used the reference numeral I to indicate generally the main housing in which my apparatus is assembled, and the numeral I I to indicate generally the cover for said housing III.

For convenience I shall hereafter in the specification generally refer to my apparatus as a turbidimeter without specific mention of its being adapted for' other uses than for liquid bacterial culture.

My improved turbidimeter includes said main,

meter I5 may be fastened to the raised portion I2 in any suitable way as here shown.

I shall describe the purpose of the foot-candle meter conjointly with that of the hereinafter mentioned photoelectric cell 40 more fully at a later point in the specification.

A thru hole II-X is provided in said cover II located in a position correspondingly with the test tube 30, said hole being somewhat larger than would be needed for insertion of a relatively smaller size tube, but large enough to accommodate a relatively larger size tube.

The cover II may be removably mounted on will of course be understood that the foot-candle the housing III in the following manner: Secured are the tongues Ill-A which project upwardly from said housing IB as shown in Flg. 1. When the cover I I is lowered into placeA on the housing I0 the exposed outer face I 0B of the tongues III- A slidably engage the inner face of the cover II at spaced points around the periphery thereof to maintain the snug and secure position of said cover II on the housing I0.

It will be understood that other suitable means may be employed to ensure the necessary and correct fitting of said cover II as here shown.

I desire it to be understoodthat while I have shown in the drawings a certain well knowntype of photoelectric cell and foot-candle meter, I make no separate claims designed for the speclilc coverage of these items as such, but I do claim as new and novel the use thereof in combination with the structure and arrangement of the several other parts of my improved turbidimeter for the purposes as herein set forth and as shown in certain views of the accompanying drawings.

I shall now describe the means by which bacteria is counted with my improved turbidimeter'.

Air intake louvers Ill-X are provided on opposite sides of said housing I0, while the aperture I 2-A is provided in the rear face of the raised portion I2 of said cover II for attachment of a vacuum hose nozzle (not shown) to withdraw from the interior of the housing the heat from the electric bulb 24 when in use.

An electric light socket member I6 is mounted for adjustment longitudinally of the main housing I0 and disposed centrally therein by means of the base member I'I having the threaded thru hole I 'I-A centrally therethru, said threaded hole I 'I-A adapted for engagement with a threaded rotatable adjusting rod I8 having at its inner end the anged head I8-A and the xed nut I8-B adapted to hold this end of said rod I8 in rotatable engagement with the angle member I9 which is integrally mounted by welding or other suitable means to the bottom of the housing l0, said rod I8 having xedly mounted on its outer end the knurled control handle |8-C.

Mounted rearwardly on said base member I'I is a supporting arm 20 carrying in fixed position on its upper end the body 2| having the thru hole 2|A, the threaded hole 2l-B and the set screw 2I-C. A slide rod 22 is adapted for slidable engagement with said thru hole 2 I-A in the body 2|, and the set screw 2I-C is, of course, adapted to set the position of said rod 22 in said body 2l in order to properly adjust and x the position of the reflector 23 which is integrally mounted on the forward end of said rod 22 for the purpose of facilitating the direction of light rays 38 from an electric light bulb 24 mounted in the socket I6. A slot 23--A is provided in the lower portion of said reector 23 to accommodate the neck 24--A of said electric bulb 24.

The electric wires 25 and 26 are secured to the contacts 25-A and 2li-A of said socket I6 and extend parallelly within the standard cord or insulation 21 thru the outlet bushing 28 mounted in the rear wall of said housing III into contact with any standard electric light receptacle by means of any standard electric cord plug.

In preparing the broth by which term I shall for convenience hereinafter refer to the liquid bacterial culture, said broth may be standardized before use, thus to establish a normal and safe basis on and from which to conduct the successive bacterial counts.

The broth 29 when suitably inoculated is placed within the test tube 30. Said testtube 30 is inserted in the tubular receptacle formed by the groove 3i in the movable vtransverse partition member 32 and the groove 33 in the ilxed transverse partition member 34, as shown in Figs. 1 and 2 in the drawings.

The coil spring members 35 extending thru the thru holes SB-A and 3IB in the transverse partition members I2 and 34 respectively serve to hold said movable transverse partition membexl 32 in yieldable contact with said fixed transverse partition member 34, thus permitting the insertion of test tubes of diilerent diameters within a reasonable scope of variation.

The flanged heads X on opposite ends of slid coil spring members 36 maintain these spring members in position as shown.

The knob members 32-A flxedly mounted on opposite ends of the movable transverse member 32 are adapted for projection thru the slots lI-B disposed in opposite sides of the housing Il so that when inserting the test tube 30 in my improved turbidlmeter either of the knobs 32-A may be grasped by the hand of the operator to cause the movable transverse member l2 to move away from the fixed transverse member 34, thus widening the space between the grooves 3l and Il to facilitate the easy insertion of the test tube l therebetween. f

A conduit member 36 is flxediy mounted in the thru hole 36-A in the fixed transverse partition member 34 and slidably engages the thru hole 36-B in the movable transverse partition member 32 to serve as a protection and passage for the electric wire 31.

A pair of horizontally and correspondingly disposed thru holes 38 and 38-A are substantially elliptical in shape and are arranged in the transverse partition members 32 and 34 respectively in direct alignment with the light rays indicated by the arrows 39 directed by said reector 23 from said electric bulb 24. These holes 3l and 38-A are of suitable width to cause the light rays thus directed to pass through the test tube 30 and its contents the broth 29 to be received by the photoelectric cell 40 (which of course is equipped with a highly light-sensitive disc), and transformed into electrical energy which is interpreted and indicated in terms of foot-candles by means of the foot-candle meter I5 being connected to and in co-operation wtih said photoelectric cell 40 by means of said electric wire l1.

It is obvious that the terminals of the positive and negative wires are connected in the usual well known manner to said photoelectric cell 4l and said foot-candle meter I5 and further detailed description here is deemed unnecessary tov enable a complete understanding thereof.

The receptacle 4I in which said photoelectric cell 40 is mounted is in turn mounted on a xed base 42. Smooth, aligned thru holes A. B, C. and D are provided in thev front wall of the housing I 0, the xed base 42, the xed transverse partition member 34, and the movable transverse partition member 32 respectively to admit said adjusting rod I8 for rotatable nonthreadable action therein.

The foot-candle readings are taken on the scale panel of the foot-candle meter I5, one example of which is shown in Fig. 2 and particularly in Fig. 4, wherein the frame 43 is shown encasing one type of scale panel 44. An open slot 45 ls indicated as extending from A" to A by the double arrow B. By means of this slot 45 different types of scale panels may be inserted for use in various types of work to be done with my lmproved turbidimeter. The indicator needle is shown by the numeral 40.

The usual procedure in counting bacteria with my turbidimeter is of course to rst standardize the broth as hereinbefore mentioned, by calibration or other suitable means. 'I'hen the test tube containing the broth is placed in the turbidimeter and the electric power turned into the electric light socket I6 to light the bulb 24.

The resulting action conjointly of the directed light rays 39 with the photoelectric cell 40 wired to the foot-candle meter I5 as hereinbefore explained enables actual counting of bacteria by foot candle readings taken at stated intervals, and at the same time enables a graphic charted record of the count, the intervals of count, and the reading in foot-candles at each count made.

By means of my turbidimeter the exact time Athe physiological and chemical changes take place may be determined within a relatively minimum length of time and with but a small part of the time and labor involved in the old well known "plate" method of counting bacteria.

The actual counting of bacteria and the graphic recording of each count is done as follows:

When the standardized broth is placed in this turbidimeter, for example, using the lower scale from 0 to 10 as shown in Fig. 4 of the drawings, at the first reading taken, say, one hour after the broth is placed in the turbidimeter, there will be but little perceptible increase in the number of bacteria present. The light rays, therefore, will continue their action on the photoelectric cell with only a slight increase of the turbidity of the broth to cut of! but a small amount of light passing through the test tube to said photoelectric cell.

It will appear obvious to those skilled in the art that as the bacteria multiplies in'the test tube the resulting increase of turbidity will close out a proportionate amount oflight rays being directed toward the photoelectric cell andthereby govern the swing of the indicator needle 46 across the scale panel 44.

For example, when the indicator needle 46 registers at 10 on the lower scale of the scale panel 44 with particular reference to Fig. 4, this indicates that 10 foot-candles of light are passing through the foot-candle meter and that the broth 29 in the test tube 30 is se or standardized to begin at 10", having a transparency to permit said 10 foot-candles of light to pass thru it.

Then, when the ,turbidity oi' the broth increases, and the indicator needle 46 moves from 10 to 8 for example, this indicates that 8 foot-candles of vlight are passing through the root-candle meter, 2 foot-candle 4meters of light having been closed oil by increased turbidity in the broth within the test tube.

Foot-candle readings are taken in reverse in column "C" in Fig. 5), with the needle 46 at 8 on the scale panel 44 the reverse reading would be interpreted as 2 (shown in column A" Fig. 5). or as .the presence of 2,000,000 bacteria (shown in column "C in Fig. 5). with the needle 46 at "7" on the scale panel 44 the reverse reading would be 3 (shown in column "A of Fig. 5), or the presence of 3,000,000 bacteria (shown in column C of Fig. 5).

The numerals shown in column B" of Fig. 5 indicate one-hour intervals in a twelve-hour time period.

It will be apparent to those skilled in the art that the diierent scales on dierent scale panels may be utilized to handle various types of liquid bacteria as well as other forms of ingredients that may be held in suspension in liquid.

As an example of a typicaLmaphic chart record of a test run in my improved turbidimeter, with particular reference to Fig. 5, the graph line "D shows -the result of a test conducted over a period of twelve-hours time, showing how. by foot-candle readings as hereinbeiore outlined the increase of turbidity of the standardized broth was actually gauged at intervals of time to enable the counting and recording of the number of bacteria per c. c. at each of said time intervals.

I claim:

1. In a device of the character described the combination of a housing, a removable cover for said housing, a photoelectric cell mounted at one end of said housing, an opening in said cover, an illumination meter mounted in said cover, said meter being visible through saidopening, said meter being also cooperatively connected with said photoelectric cell. an opaque wall comprising two members mounted transversely of said housing adjacent said cell, one of said wall members b'eing iixed and the other movable longitudinally of the housing, said wall members having aligned windows therethrough, and also having aligned grooves in the faces thereof forming -a socket, a transparent receptacle inserted in said socket, a light bulb mounted for longitudinal adjustment on the opposite side of said wall i'rom said cell, said cell, windows, receptacle and bulb being in longitudinal. alignment with one another, and coil springs having their ends attached to said members to force the movable'member toward the xed member.

2. In a device of the character described the combination of a housing, a removable cover for said housing, a photoelectric cell mounted at one end of said housing, an opening in said cover, an illumination meter mounted in said cover, said meter being visible through said opening, said meter being also cooperatively connected with said photoelectric cell. an opaque wall comprising two members mounted transversely of said housing adjacent said cell, one of said wall members being xed and the other movable longitudinally of the housing, said wall kmembers having aligned windows therethrough, and also having aligned grooves in the facesthereof forming a socket, a transparent receptacle inserted in said socket, a light bulb mounted for longitudinal adjustment on the opposite side of said` wall from said cell, said cell, windows. receptacle and bulb being in ,longitudinal alignment with one another, and coil springs having their ends attached to said members to force the movable member toward the iixedmember, and a projection on each end of said movable member and extending outside said housing for manually moving 'said movable member apart from said xed member.

SHERMAN P. SPARKS. 

